KR20030022275A - Suction and discharge valve arrangement for a small hermetic compressor - Google Patents

Abstract

One end is closed by a valve plate 10, the valve plate 10 of the type comprising a compression cylinder 1 having a suction pipe 5 adjacent thereto and disposed generally perpendicular to the axis of the cylinder. In the intake and discharge valve arrangement for a small hermetic compressor, the valve plate 10 has a discharge orifice 11 and a suction passage P which are generally centered with respect to the axial projection 20 of the inner contour of the compression cylinder 1. Has at least one suction orifice 12 which forms an extension of at least a portion of the head and is directed into the axial protrusion 20 of the inner contour of the compression cylinder 1, the suction passage P having an end thereof Is opened towards the inside of the compression cylinder 1, the opposite end of which is connected to the suction pipe 5 by a transition part T which is opened towards the suction pipe 5 and configured to minimize the load loss.

Description

Suction and discharge valve arrangement for a small hermetic compressor

The efficiency of the small hermetic compressor of the refrigeration system is affected by the performance of the valve that controls the gas flow.

Compressors in domestic refrigeration systems use unidirectional valves that control the flow of gas during operation. The intake valve controls the flow of gas, which flows out of the suction line connected to the low pressure side of the refrigeration system and through the compression cylinder while the discharge valve controls the precompressed gas to the high pressure side of the refrigeration system. Comes out.

The inlet and outlet valves generally comprise one or more gas passage orifices and vanes attached to one end thereof. Thus, even if a pressure difference occurs through the valve, the vanes are displaced to allow the gas to pass in the desired direction.

To facilitate the manufacturing process, the suction and discharge orifices generally have a circular cross section and are constructed on a steel plate known as a valve plate. In most cases, when the hermetic compressor is compact, the geometry of the intake valve, intake orifice, and outlet orifice is similar to that in which the precompressed gas must be separated from the gas under intake pressure (primarily carried out by the cylinder cover). This causes the discharge orifice to be disposed very close to the wall of the cylinder (FIG. 1) off center with respect to the central axis of the compression cylinder. Thus, the suction orifice may be included in the axial projection of the inner contour of the compression cylinder keeping a constant minimum distance with respect to the discharge orifice.

However, during discharge, it is necessary to supply gas with additional power before operating the refrigeration system in order to eliminate energy losses in the valves and the discharge muffler. This additional power is also called add-pressure, which reduces the efficiency of the compressor. In this state, the piston is located very close to the upper dead center of the machine, forming a low height compression chamber that significantly increases the load loss of the gas flowing into the discharge orifice and passing through the discharge valve. The more the position of the exit orifice is off center, the greater the power loss. An example of this phenomenon is described in Brazilian patent PI 6,793,538, where this effect is discussed with regard to the irregular loading on vanes that affect reliability. However, in this conventional solution, since it is not a compact compressor, the discharge orifice can be located in the center of the compression chamber.

In medium and large compressor constructions, the cylinder cover region flows from the suction pipe to the suction orifice by a curve and cross section with a radius such that the entire cross section of the suction orifice is all uniformly used by the flow of gas from the suction pipe. There is enough room to redirect the gas flow. The bending provided in the gas flow passing from the suction pipe to the suction orifice (s) can be made so that the entire cross section of the suction orifice is properly used as the gas flow passage.

Furthermore, as mentioned above, the utilization of space in this state must be presented in a solution as described in patent 6,793,538. Here, a suction chamber is provided in the cylinder head which is open directly towards the suction orifice, eliminating the problem resulting from a sharp change in the gas flow flowing directly from the suction pipe to the suction orifice (s).

During compression, the intake valve is subjected to a load calculated by the formula (Pcil-Ps) Ao (where Pcil is the pressure in the cylinder, Ps is the vapor pressure and Ao is the area of the orifice). In a known solution of the vane structure for the intake valve, the vanes bend over the intake orifice and are subjected to bending stress. When the bending stress is higher than the fatigue stress limit of the vane material, the valve ruptures due to the bending fatigue. The stress on the vane functions in the form of an orifice. The circular orifice exerts high stress on the valve at exactly the center point because the center point is at the same distance from the area where the valve is seated.

The present invention relates to inlet and outlet valve devices for hermetic compressors of the type used in small refrigeration units such as refrigerators, freezers, chillers and the like.

Figure 1 shows a suction valve, a suction orifice and a discharge orifice constructed in accordance with the prior art and schematically shows a plan view of the valve plate as seen from the compression cylinder side.

Figure 2 schematically shows a longitudinal cross-sectional view of a valve plate of the valve arrangement of the invention connected to a cylinder cover and a suction muffler.

FIG. 3 schematically shows a plan view when the valve plate of the valve device of the present invention is connected to the suction muffler shown in FIG. 2.

FIG. 4 schematically shows a top view of the valve plate of FIG. 3, similar to FIG. 1 but without the intake valve.

It is therefore an object of the present invention to provide a inlet and outlet valve arrangement for a compact hermetic compressor which allows the outlet orifice to be placed on the valve plate in order to minimize the pressure differential present in the prior art structure. If the pressure differential is minimized, during compression, power dissipation and loss of load are reduced without compromising the effective gas flow area through the suction orifice, such as the minimum space of the discharge orifice.

This and other objects are achieved through inlet and outlet valve arrangements for compact hermetic compressors of the type comprising a compression cylinder. The compression cylinder is supplied by a suction pipe whose one end is closed by a valve plate and adjacent to the valve plate and disposed generally perpendicular to the cylinder axis. The valve plate maintains a constant minimum space of the discharge orifice and the discharge orifice generally centered relative to the axial protrusion of the internal contour of the compression cylinder and forms at least a portion of the suction passage so as to form at least a portion of the suction passage. At least one suction orifice is provided that is internal to the protrusion and external to the contour of the discharge orifice. The suction passage is open to the suction pipe, one end of which is open to the inside of the compression cylinder, and the opposite end of which is cooperating with one of the portions formed by the suction passage and the suction pipe. The suction passage has a cross section configured to change the direction of the gas flow in a direction such that the entire cross section of the suction orifice is fully utilized as the gas flow passage.

The present invention describes a compact hermetic compressor. The compact hermetic compressor comprises a motor-compressor assembly having a cylinder block, which forms a compression cylinder 1, inside a shell (not shown), the compression cylinder 1 having a inside of the motor-compressor assembly. When driven by an electric motor, it accommodates a reciprocating piston that absorbs and compresses refrigerant gas. One end of the compression cylinder 1 is closed by a valve plate 10, which valve plate 10 is attached to the cylinder block, and the discharge orifice 11 and the at least one suction orifice 12 are closed. And a compression chamber 2 is formed between the piston top in the compression cylinder 1 and the valve plate 10. The cylinder block further has a cylinder lid 3 attached to the valve plate 10 to separate the high pressure side from the low pressure side and forming an intake and discharge chamber (not shown) therein. These chambers may optionally be in fluid communication with the compression chamber 2 through the discharge orifice 11 and the suction orifice 12. Each keeps communicating. These optional The communication is formed by opening and closing the inlet and outlet valves, which are in the form of valve vanes acting on the inlet orifice 12 and outlet orifice 11, respectively. The valve plate 10 further has a suction muffler 4 (FIGS. 2 and 3).

In the structure of the compact compressor, as described below, a suction pipe 5 adjacent to the valve plate 10 and disposed substantially perpendicular to the cylinder axis is formed through the cylinder lid 3. In the structure shown, this suction pipe 5 is formed by a pipe that feeds gas into the suction orifice 12 through the cylinder cover.

According to this embodiment, the suction pipe is connected to the suction muffler 4.

According to the invention, the valve plate 10 has a discharge orifice 11 and at least one suction disposed generally centrally thereon with respect to the axial protrusion 20 (diameter D) of the inner contour of the compression cylinder 1. It has an orifice 12. At least one suction orifice 12 is disposed therein with respect to the axial protrusion 20 of the inner contour of the compression cylinder 1 to maintain a constant minimum radial spacing d of the discharge orifice 11. It is arranged outside with respect to the contour of (11). This constant minimum radial spacing d is formed on at least one surface of the valve plate 10 facing inwardly of the compression cylinder 1, and prevents gas from excessively escaping from the high pressure side to the low pressure side and seals gasket 5 ) To calculate the thickness of the wall that can adequately press.

The spacing between the orifices on both sides of the valve plate 10 is determined so that a larger sealing space can be obtained between the suction side and the discharge side. In the structure shown, the radial spacing between the adjacent orifices of the discharge orifice 11 and the suction orifice 12, which are located inwardly and facing each other of the compression cylinder 1, is, for example, a constant minimum radial spacing d Is less than

According to the invention, the discharge orifice 11 is circular and coaxial with the inner contour of the compression cylinder 1. The suction orifice 12 is in the form of an annular fan shape (small dimension d1, large dimension d2) which is generally centered with at least one inner contour of the discharge orifice 11 and the compression cylinder 1.

In this embodiment, the suction orifice 12 completely forms the suction passage P, which end thereof is opened inside the compression cylinder 1, and the opposite end thereof is sucked in. It is open to the pipe 5 and is connected to the suction pipe 5 by a transition part T. This transition part T is generally in the form of a duct part, the inner contour of which is at least partly bent and cooperates with one of the parts formed by the suction passage P and the suction pipe 5. The suction passage P has a cross section configured to be able to change the direction of the gas flow exiting the suction pipe 5 in a direction necessary and necessary to keep the entire cross section of the suction orifice 12 fully utilized as the gas flow passage. Have

In the described solution, the transition portion T is formed by the end of the suction orifice 12 facing the suction pipe 5, which changes the direction of the gas flow received in the transition portion T. It has a cross section configured to maximize the radius of the bend. The gas flow received in the transition portion T passes from the suction pipe 5 to the suction passage P, and in the illustrated configuration, the suction passage P is a suction orifice disposed through the valve plate 10. It is formed completely by (12).

According to the invention, as mentioned above, the cross section of the transition portion T formed by the suction orifice 12 allows the gas to be received along the curvature necessary to maximize the use of the cross section of the suction orifice 12. Because it is more useful.

In a variant of the present solution, the structure of the transition portion T (not shown) is provided with a suction pipe 5, a suction muffler 4, or to provide the desired curvature such that the gas flow is received in the compression cylinder 1. It can also be obtained from the cylinder cover 3. In another structural option, the bending of the gas flow path towards the inside of the compression cylinder 1 is carried out at the inner part of the transition portion T formed by the gas introduction end 12a of the suction orifice 12. Can be obtained by a step provided in front of 12).

According to this embodiment, the suction orifice 12 has its gas introduction end 12a open to the valve plate 10 opposite to that which is directed inwardly of the compression cylinder 1 and directly connected to the suction pipe 5, A transition portion T is formed and is opened to the gas discharge end 12b, the valve plate 10 facing inward of the compression cylinder 1.

In the solution of the invention, the suction orifice 12 provided on the valve plate 10 no longer provides a wall having a constant dimension along the cylindrical contour and the thickness of the valve plate 10.

According to an embodiment, the gas introduction end 12a of the intake orifice 12 forms a transition portion T and has a cross section larger than that of the gas discharge end 12b. The gas introduction end 12a further provides a portion of the wall that penetrates through the thickness of the valve plate 10 and gathers in a bow shape as part of its contour, thereby forming a gas receiving funnel, in this region. The sudden change in the direction of the gas flow to the valve plate 10 is reduced, and as a result, in the valve plate 10, a sudden change in the gas flow direction from the suction pipe 5 into the suction orifice 12 occurs. Minimize the loss of load.

The suction orifice 12 provides the shape and dimensions formed as a function of the axial protrusion of the contour of the compression cylinder 1 to optimize the gas flow through the valve plate 10 without causing loss of high loads. Adjacent to the contour of the discharge orifice 11 is to provide a minimum distance d between the contours.

The suction orifice 12 of the present invention has a suction orifice 12 even when the high flow area of the gas flow is the same as the geometric area of the gas passage, and the gas supply from the suction pipe is perpendicular to and adjacent to the suction orifice 12. It substantially uses the geometric region of and has the major advantage of optimizing the relationship between the thickness of the valve vane and the region of the suction orifice 12, which reduces the power dissipation in the suction valve.

According to the invention, the valve plate 10 is attached to the intake valve vane 30 by an end portion 31 of the intake valve vane 30, on the side facing inwardly of the compression cylinder 1. The other end portion 32 is displaced between a closed valve position which closes the suction orifice 12 by an elastic deformation and an open valve position which opens the suction orifice 12, the suction valve vane being of the compression cylinder 1. It is located inside the axial protrusion 20 of the inner contour and outside the axial protrusion of the contour of the discharge orifice 11.

According to an embodiment, the intake valve vanes 30 have a generally "U" shaped contour. The underside of the "U" contour forms another end portion 32, the end portions 31, 32 facing each other, the valve plate 10 opposite to the contour of the discharge orifice 11. Located in the area of). The proposed solution provides a new coupling structure of the suction orifice 12 which allows the outlet orifice 11 to be placed as close as possible to the central region of the compression cylinder 1.

An important point in centering the discharge orifice 11 is that the compressed gas is discharged when the piston is very close to the upper dead center of the machine. In this case, centering the discharge orifice 11 reduces the pressure difference along the compression cylinder 1 while the compressed gas is discharged through the discharge valve. This reduction in pressure difference results in a reduction in power dissipation during compression, which increases the efficiency of the compressor.

A “U” shaped intake valve, for example a suction valve with a small inlet radius as shown in FIGS. 3 and 4, deforms the engagement structure of the intake orifice 12. This fully utilized form of the suction orifice 12 has a cross section that bends about 90 ° before passing through the suction orifice to affect the gas flow exiting the suction muffler 4.

As a function of the engagement structure of the suction orifice of the present invention, the suction valve vanes may be smaller than the thickness of the vanes of the prior art which reduce the loss while maintaining the same reliability and while inhaling. The solution achieves these advantages by minimizing bending stress on the suction valve vanes in the region of the suction orifice during discharge.

In the structure of the present invention, the suction valve vanes are generally seated at the edges defining the suction orifice 12 and radially spaced d1. Thus, for example, even if d2 is greater than D, the final stress exerted on the valve is small compared to the cylindrical suction orifice.

With the structure of the present invention for the suction orifice, it is possible to reduce the maximum bending stress of the suction valve vanes in the region of the orifice with respect to the maximum stress foreseen in the cylindrical orifice. In addition, the use of valve vanes of smaller thickness reduces the power dissipation of these elements during inhalation and increases efficiency.

Claims (10)

One end is closed by a valve plate 10, the valve plate 10 being of a type comprising a compression cylinder 1 provided by a suction pipe 5 adjacent thereto and arranged generally perpendicular to the axis of the cylinder. In the inlet and outlet valve arrangement for a small hermetic compressor, the valve plate (10) is provided with at least a discharge orifice (11) disposed generally centrally with respect to the axial protrusion (20) of the inner contour of the compression cylinder (1). One suction orifice 12 is provided, wherein the at least one suction orifice 12 maintains a constant minimum distance of the discharge orifice 11 and forms at least a portion of the suction passage P. Is located internally relative to the axial protrusion 20 of the inner contour of the outer contour relative to the contour of the discharge orifice 11, the suction passage P, one end of which is towards the interior of the compression cylinder 1 Open, opposite ends Is connected to the suction pipe 5 by means of a transition portion T which opens toward the suction pipe 5 and cooperates with the suction passage P and one of the portions formed by the suction pipe 5, and the suction orifice ( 12. A suction and discharge valve device for a small hermetic compressor, characterized in that it has a cross section configured to change the direction of the gas flow in a direction such that the entire cross section of 12) is fully utilized as the gas flow passage. 2. The compact hermetic compressor according to claim 1, characterized in that the transition portion (T) forms a duct portion which connects the suction pipe (5) to the suction passage (P) and whose inner contour is at least partially bent. Intake and discharge valve device. The suction and discharge valve device for a compact hermetic compressor according to claim 2, wherein the transition portion (T) cooperates with the suction passage (P). 4. The suction according to claim 3, wherein the suction passage (P) comprises a gas introduction end (12a) that engages with the suction pipe (5) and a gas discharge end (12b) that is open toward the inside of the compression cylinder (1). Inlet and outlet valve device for a compact hermetic compressor, characterized by being formed by an orifice (12). 5. The small hermetic type according to claim 4, wherein the transition portion (T) is formed by the gas introduction end (12a) of the suction orifice (12) in which part of the contour is bent to form a gas introduction contour. Inlet and outlet valve device for compressor. 5. The valve plate (10) according to claim 4, wherein the valve plate (10) is attached to one end of the suction valve vanes (30) on the side facing the inside of the compression cylinder, and the other end portion (32) is sucked by the elastic deformation of the vanes. Displaced between a closed valve position that blocks the orifice 12 and an open valve position that opens the suction orifice 12, wherein the suction valve vanes 30 are inside the axial protrusion 20 of the internal contour of the compression cylinder 1. And an inlet and outlet valve device for a small hermetic compressor, characterized in that it is located outside the axial projection of the contour of the outlet orifice (11). 7. The valve part (10) according to claim 6, wherein the end portions (31, 32) of the intake valve vanes (30) are located in the region of the valve plate (10) opposite to each other and arranged opposite to the contour of the discharge orifice (11). Inlet and outlet valve device for a compact hermetic compressor, characterized in that. 8. A suction and discharge valve arrangement for a compact hermetic compressor according to claim 7, characterized in that the suction valve vanes (30) provide a generally "U" contour. 2. A suction according to claim 1, characterized in that the suction orifice (12) is an annular fan-shaped concentric substantially at least one of the inner contours of the compression cylinder (1) and the discharge orifice (11). And discharge valve device. 2. A suction and discharge valve arrangement for a compact hermetic compressor according to claim 1, characterized in that the discharge orifice (11) is circular and coaxial with the inner contour of the compression cylinder (1).